Safety catheter system and method

ABSTRACT

A catheter integral with a valved needle-free connector provides a safety catheter device configured to receive a blunt cannula and sharp needle forming an insertion mechanism. The sharp needle is mounted within a needle tube and a control handle is used to slide the sharp needle out of and into the protective needle tube. When the insertion mechanism is mounted to the connector and the control handle is used to slide the sharp needle out of the tube, a blunt cannula first moves into contact with and enters the bore of the valve mechanism of the connector opening it and protecting it from damage that may be caused by the sharp needle. The sharp needle is then extended through the connector and extends out the distal end of the catheter so that a venipuncture procedure may be performed to properly locate the catheter in the patient&#39;s circulatory system. Once located, the needle may be retracted into the insertion mechanism, the insertion mechanism disconnected from the connector, and discarded.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/225,229, filed on Sep. 2, 2011, U.S. Pat. No. 8,740,850, which is acontinuation of U.S. application Ser. No. 11/585,434, filed on Oct. 23,2006, now U.S. Pat. No. 8,029,472, which is a continuation of U.S.application Ser. No. 10/334,125, filed on Dec. 30, 2002, now U.S. Pat.No. 7,125,396, all of which are incorporated herein by reference.

BACKGROUND

The present invention relates generally to intravenous catheters, andmore particularly to an intravenous catheter having a connector operablewith a blunt cannula to control the flow of fluid through the IVcatheter.

Intravenous (IV) therapy is a versatile technique used for theadministration of medical fluids to patients. It has been used forvarious purposes such as the maintenance of fluid and electrolytebalance, the transfusion of blood, the administration of nutritionalsupplements, chemotherapy, and the administration of drugs andmedications. Fluids may be administered intravenously by injectionthrough a hypodermic syringe, or intermittently or continuously byinfusion using a needle or a plastic or silicone catheter.

Although there are many advantages to be derived by the patient from theintravenous administration of fluids, the past two decades have broughtheightened awareness of the risks of propagating infectious diseasesassociated with the technique, particularly due to the HIV virus. Onemethod by which infectious disease may be spread is an inadvertentpuncture of medical personnel by the sharp needle that was used toinsert an IV catheter into an infected patient. Such needles areextremely sharp and should the insertion site become wet withadministration fluid or blood, the medical personnel may inadvertentlypuncture herself or himself while handling the sharp needle. Any openingin the skin raises the possibility of contracting an infection.

One consequence of this heightened awareness has been the development ofvarious devices designed to reduce the risk of spreading infectiousdiseases during the IV procedure. Devices have been developed over theyears to attempt to lower the risk of such inadvertent punctures. Onesuch class of devices has been the blunt cannula approach to connectors.In this class of connectors, sharp needles are not used. In one approachin this class, the connecting devices have been designed based on theLuer system of connectors in which the mating surfaces are tapered.While this approach has advanced the safety of health care workerssubstantially, a venipuncture procedure still requires the use of asharp needle.

Another class of devices developed in the venipuncture area is thesafety needle. This is a type of needle housed inside a protectiveguard. It comprises a sharp needle that may be extended from andretracted into the protective guard, the purpose of which is to lessenthe chance of an inadvertent needle puncture of medical personnel. Itprovides the required sharp needle for the venipuncture procedure butcarefully guards the operator against the sharp needle except for theone time it is extended to pierce the patient. In some versions, thesharp needle is locked within the protective guard once it has beenretracted. The possibility of an inadvertent puncture is further reducedwith such an arrangement.

Catheters used for peripheral IV therapy tend to be relatively short,between 19 mm and 32 mm long, although they are occasionally 50.8 mmlong for insertion into a deep vein. A peripheral IV catheter is made ofsoft, flexible plastic or silicone, generally between 16 gauge and 24gauge. In the conventional venipuncture procedure, the catheter isinserted into a vein in the patient's hand, foot, or the inner aspect ofthe arm or any vein in the body that will accept an IV catheter.

IV catheters are used to provide fluid to or to withdraw fluid from apatient. In order to properly place an IV catheter in a patient's vein,a sharp introducer needle must be used to puncture the skin, tissue, andvein wall to provide a path for placement of the catheter in the vein.Typical IV catheters are “over-the needle” catheters where the catheteris coaxially placed over the needle. The catheter thus rides with theneedle through the skin, tissue, and vein wall and into the patient'svein. When the needle pierces the vein, blood will “flashback” into theneedle. Thus, once the clinician observes this flashback of blood, theclinician will know that the catheter and needle have been inserted inthe vein. The needle can then be withdrawn from the patient and thecatheter can be advanced further into the vein as desired.

In further detail, a tourniquet is applied proximal to the venipuncturesite and a variety of techniques may be used to dilate the vein. Whilewearing disposable gloves, the medical technician cleanses thevenipuncture site and a vein is retracted or anchored by placing a thumbover the vein about 50 mm to 75 mm distal to the site. A catheter with asharp stylet or needle advanced through its lumen so that the sharp tipextends beyond the cannula of the catheter, or a butterfly needle, isintroduced into the vein by inserting the bevel into the vein at about a20 degree to 30 degree angle with the bevel facing up in order to pierceone wall of the vein. Blood return in the tubing of the butterfly needleor a flashback chamber of the over-the-needle catheter indicates thatthe vein has been entered, and the needle is lowered towards the skin todecrease the entry angle and the catheter is advanced about 6.35 mm intothe vein. The sharp needle or stylet is loosened and the catheter isgently advanced farther up into the vein until the hub of the catheteris against the venipuncture site. The tourniquet is loosened and thesharp needle or stylet is removed from the catheter. The needle adaptorof the infusion tubing is secured to the hub of the catheter, and theroller clamp is opened. The flow rate may be controlled either byadjusting the amount of pressure exerted by the roller clamp or byadjusting the infusion rate of an infusion pump. The catheter is securedto the venipuncture site by gauze and adhesive tape.

During the above venipuncture procedure, medical personnel are exposedto the possibility of an accidental needle puncture or to contaminationfrom the back flow of the patient's blood from the venipuncture site.While care is usually taken to avoid a puncture of the medicalpersonnel, circumstances may arise during which a puncture of themedical personnel may nevertheless occur exposing the health carepersonnel to any infectious blood borne diseases carried by the patient.

Devices have been developed to reduce the risk of such accidental needlepunctures, but a need has been recognized for devices that efficientlyprevent the back flow of blood while providing a swabbable female Luerport. In one case, there has been provided an intravenous catheterinsertion apparatus that includes a catheter integral with a connectorhaving a pre-slit septum. A blunt cannula is used to penetrate thepre-slit septum and a needle tube having a sharp needle of sufficientlength to pass through the blunt cannula, the connector, and thecatheter is attached leaving the sharp tip of the needle projectingbeyond the end of the catheter. After the catheter has been insertedinto the blood vessel of the patient, the needle tube and blunt cannulamay be removed from the connector/catheter device and during removal,the septum of the injection site prevents blood from leaking out of thecatheter. Also during removal, the sharp needle tip may be withdrawninto the needle tube that provides a guard over the sharp needle tip toprotect the medical personnel performing the IV procedure from puncture.

However, a problem that may result from such an assembly using apre-slit septum in the connector/catheter device is the possibility ofdamage to the septum due to the blunt cannula being repeatedly forcedinto the normally closed pre-slit septum. A damaged septum may leakblood and this may then expose a health care provider to any infectiousdiseases contained in the blood. A further problem that may arise duringthe use of such an assembly is that some guarded needle devicesavailable today are somewhat complex with multiple stops and lockingdevices designed to protect the medical personnel from needle punctures.Unfortunately, the action of sliding the needle into the fluid pathcreated by the blunt cannula and the pre-slit septum with these complexdevices may require more than one physical hand movement by the medicalpersonnel operating the assembly. Because medical personnel are quitebusy, any additional efforts required to accomplish tasks areundesirable. Further, the requirement of extremely fine motor skillsduring the placement of a sharp needle in a catheter and into a patientcan result in inadvertent damage to the connector of the catheterresulting in blood leakage.

Pre-slit septum systems also do not typically allow access to thecatheter with standard male Luer connectors. An adapter is required,which is not desirable. In addition to the expense of an additionalpart, such adapters can get lost or may not be in stock when needed.

Hence, those skilled in the art have recognized a need for a safetycatheter insertion device that provides increased protection from needlepunctures to medical personnel handling the device. Additionally, a needhas been recognized for a more reliable insertion device that is lesslikely to leak a patient's blood after removal of the catheter needleand even after continued reuse of the device. A further need has beenrecognized for an insertion device that is easier to use so that lesseffort, steps, and time are required to accomplish the placement in thepatient. And furthermore, an insertion device that is easier tomanufacture and that is cost effective is also needed. The presentinvention satisfies these needs and others.

SUMMARY OF THE INVENTION

Briefly, and in general terms, the invention is directed to a safetycatheter system and method that provides access to a biological site. Inone aspect, the safety catheter system comprises a catheter defining alumen and having a first end for insertion into the biological site anda second end connected to a valved connector for controlling the flow offluid through the lumen of the catheter. The connector has an internalfluid passageway by which fluid may flow through the connector with theconnector comprising a housing having a first port and a second port,the first port being adapted to receive a blunt cannula, such as a maleLuer fitting, and the second port being connected to the second end ofthe catheter. A movable element is positioned within the housing, themovable element having a first position at which the movable elementblocks fluid flow through the housing and a second position at which themovable element permits fluid flow through the housing. In a moredetailed aspect, the movable element comprises a head defining a boreforming a part of the fluid passageway through the connector, the headbeing configured such that when the movable element is in the secondposition, the bore assumes it naturally open configuration therebypermitting fluid flow through the connector and cannula, the head beingfurther configured such that when the moveable element is in the firstposition, the bore moves to a closed configuration preventing fluidflow.

In more detailed aspects, the safety catheter further comprises aninsertion mechanism that comprises a blunt cannula adapted for insertionthrough the first port of the housing and into contact with the head ofthe movable element to move the movable element to the second positionat which position the bore opens. The blunt cannula is also adapted toslide within the opened bore of the head of the movable element toprotect the movable element, and a needle having a sharp tip is slidablyengaged with the blunt cannula and is adapted to extend through theblunt cannula after the blunt cannula has slid within the bore of themovable element, and to slide through the catheter until the sharp tipprojects beyond the first end of the catheter so that the sharp tip maypenetrate the biological site. The insertion mechanism comprises aneedle tube in which is located the blunt cannula and the sharp needle.The needle tube comprises threads located adjacent the first port thatthreadably engage the needle tube.

In yet other aspects, the needle tube of the safety catheter system andmethod further comprises a control handle that controls the position ofthe blunt cannula and the sharp needle. The control handle is configuredsuch that when it is in a retracted position, the sharp tip of theneedle is covered by the needle tube to protect a clinician from beingpunctured by the sharp tip. When the control handle is in the extendedposition, the blunt cannula first protrudes from the needle tube toengage the movable element of the connector as described above, and thesharp needle is then extended from the needle tube to extend through theconnector and the cannula so that the biological site may be accessed.Further, the needle tube comprises a limiting device adapted to limitthe sliding travel of the blunt cannula, and is further adapted toprovide a restraint against the sharp needle tip projecting beyond theend of the blunt cannula before the blunt cannula reaches the limit oftravel.

In another aspect, the needle tube comprises a locking device to retainthe needle in a retracted position within the needle tube once the sharpneedle has been retracted. The locking device permanently retains thesharp tip of the needle within the tube to protect clinicians againstbeing punctured by the needle. In another aspect, the movable elementincludes a head having a bore through which fluid flows through theconnector. The bore is marquise-shaped and is naturally open. Theconnector includes a larger inner diameter section at the secondposition of the movable element such that the bore may resume itsnaturally open configuration and permit fluid flow through the connectorand the catheter.

In accordance with method aspects of the invention, there is provided amethod for providing access to a biological site through placement of acatheter in the site. The method comprises moving a blunt cannula into afirst port of a connector into contact with a movable element of theconnector to move the movable element into a housing of the connector toa position where the movable element opens to permit flow of fluidthrough the connector, the blunt cannula also moving into the opening ofthe movable element to provide protection to the movable element,sliding a needle having a sharp tip through the blunt cannula andthrough a catheter connected to the connector so that the sharp tip ofthe needle extends beyond the catheter a sufficient length that enablesan operator to access a biological site with the sharp needle andcatheter. retracting the sharp needle from the catheter and the bluntcannula, removing the blunt cannula from the connector, and moving themovable element of the connector to a closed position at which themovable element prevents flow of fluid through the catheter.

In accordance with more detailed aspects, the method further comprisesthe step of protecting the sharp tip of the needle with a physicalbarrier whereby the possibilities of a operator being punctured with thesharp tip are reduced. Further, the of moving a blunt cannula into afirst port of a connector into contact with a movable element comprisesmoving the movable element into a second position within a housing ofthe connector at which position a bore through the movable elementresumes its naturally open shape providing a fluid flow passagewaythrough the connector, and moving the blunt cannula into the bore of themovable element to provide protection to the movable element.Additionally, the method further comprises the steps of limiting themovement of the blunt cannula to a position within the connector toentering the open bore, and restraining the sharp needle tip fromprojecting beyond an end of the blunt cannula before the blunt cannulareaches the limit of its movement.

In yet further detailed aspects, the method further comprises the stepsof threadably connecting an insertion mechanism to the connector, theinsertion mechanism containing the blunt cannula and the sharp needle,and unthreading the insertion device from the connector after thebiological site has been accessed whereby the insertion devicecontaining the sharp needle may be discarded. Additionally, the methodfurther comprises the steps of controlling the position of the sharpneedle in the insertion mechanism with a control handle, wherein movingthe control handle to a retracted position causes the sharp needle to bemoved to a retracted position within the insertion mechanism so that theinsertion mechanism covers the sharp tip of the needle, and moving thecontrol handle to an extended position causes the sharp needle to beextended from the insertion mechanism so that the sharp needle may beextended through the catheter and used to access the biological site. Inyet a further step, the method comprises locking the sharp needle in aretracted position within the insertion mechanism after its use inaccessing the biological site at which position the sharp tip of theneedle is protected.

Other features and advantages of the present invention will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings, which illustrate, by way of example, theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an intravenous safety catheter system inaccordance with aspects of the invention, the system having a safetycatheter device with a sharp needle insertion mechanism mounted to thesafety catheter device, and as shown, the insertion device has beenactivated to extend the sharp tip of the needle from the proximal end ofthe catheter in preparation for a venipuncture procedure;

FIG. 2 is a side, elevation view of the safety catheter system of FIG. 1that has been rotated approximately ninety degrees and shows theinsertion mechanism in the pre-use configuration with a control handleof the insertion mechanism located at the proximal, pre-use positionwhere a blunt cannula and the sharp needle are both retracted in theneedle tube;

FIG. 3 is a cross sectional view of the safety catheter system of FIG. 2rotated ninety degrees from the view of FIG. 2 and showing internaldetails of the insertion mechanism connected to a valved connector whichis in turn connected to a catheter for accessing a biological site;

FIGS. 4 and 5 are respectively a side, elevation view and a sidecross-sectional view of a valved connector that may be used to form apart of the safety catheter system shown in FIGS. 1 through 3, theconnector shown having a female Luer port, a movable element in the formof a piston, and a male Luer port at its distal end;

FIGS. 6 and 7 are cross-sectional views of the movable piston element ofthe valved connector of FIGS. 4 and 5, the views being rotated at ninetydegrees to each other;

FIG. 8 is a side, elevation view showing the insertion mechanism mountedto the connector of FIG. 4;

FIG. 9 is a cross-sectional view of FIG. 8 showing the insertionmechanism threadably mounted to the connector with the blunt cannulaengaged with the bore of the piston element of the connector, the bluntcannula having entered the open bore of the piston and therebyprotecting the bore of the piston element prior to insertion of thesharp needle through the piston element;

FIG. 10 shows the position of the control handle on the needle tube asthe blunt cannula is moved into the position shown in FIG. 9;

FIG. 11 is a cross sectional view of FIG. 10 showing a blunt cannulacontrol tube locked into position with the blunt cannula thereforelocked in position, as shown in FIG. 9;

FIG. 12 is a full side, elevation view of the safety catheter system asshown in FIG. 1 in which the insertion mechanism is in the fullyactivated configuration thereby causing the sharp tip of the needle toprotrude from the distal end of the catheter in preparation forperformance of a venipuncture procedure;

FIG. 13 is a cross-sectional view of FIG. 12;

FIG. 14 is a schematic view showing the operation of the control handleof the needle tube after the venipuncture procedure has been completed;

FIG. 15 is a side cross-sectional view of the proximal end of the needletube showing the connection of the control handle with a flashbackchamber attached to the sharp needle;

FIG. 16 is a rotated view of part of FIG. 15 showing a control handlelock that will function to retain the sharp needle within the needletube permanently;

FIG. 17 is a schematic view showing the disconnection of the insertionmechanism from the connector/catheter device after the biological sitehas been accessed;

FIGS. 18 and 19 are respectively a full, side, elevation view and across-sectional view of an alternate safety catheter connector/catheterdevice showing the valved connector and the flexible catheterpermanently mounted together; and

FIGS. 20 and 21 are cross-sectional views of a positive bolus valvedconnector usable with the safety catheter system in accordance with analternate embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings in which like reference numerals indicatelike or similar elements among the several views, FIGS. 1, 2, and 3 showdifferent views of an intravenous safety catheter insertion device 30comprising a safety catheter device 32 to which is mounted an insertionmechanism 34. The safety catheter device 32 comprises a catheter 36 anda valved connector 38 mounted to the catheter. The catheter 36 is of aconventional type well known in the art, and comprises a soft flexiblebody or tube 40 made from plastic or silicone mounted at its proximalend 42 to the distal end 44 of the connector 38. In this embodiment, thecatheter tube 40 is connected to the connector 38 with a female Lueradapter 46. The catheter tube 40 is generally between 19 mm (0.75inches) and 31.75 mm (1.25 inches) in length and between 16 and 24 gaugein diameter, although other sizes may be used. The insertion mechanism34 comprises a needle tube 48 within which is housed a sharp needle 50(FIG. 3). The needle is slidable in the needle tube 48. It should benoted that FIG. 1 shows the sharp needle 50 in an extended configurationwith the sharp tip apparent beyond the end of the catheter tube 40 inpreparation for performing a venipuncture procedure. FIGS. 2 and 3however show the sharp needle 50 in a retracted position with the needlefully protected by the needle tube 48.

The connector 38 shown in this embodiment is the ALARIS Medical Systems,Inc. SmartSite® connector having an internal valve. See for example U.S.Pat. No. 5,676,346 to Leinsing, entitled “Needleless Connector Valve”issued Oct. 14, 1997, incorporated herein by reference. At the proximalend of the connector 52, there are threads 54 and a female Luer adapterport 56 to which the sharp needle insertion mechanism 34 is mounted. Atthe distal end of the connector 44 the catheter is permanently mounted,as will be discussed in further detail below.

Regarding the view of the insertion mechanism 34 in FIG. 1, a controlhandle 58 is shown that slides on the tube 48 of the insertion device tocontrol the relative positions of internal components relative to theconnector 38. An access slot 60 can be seen in the wall of the needletube 48 through which the control handle connects with internalcomponents to move them in accordance with movement of the controlhandle. In the configuration of FIG. 1, the control handle 58 is in itsdistal position which has caused the sharp needle 50 to extend throughthe connector 38, through the catheter 36, and to extend from the distalend of the catheter for use in penetrating the patient's skin and bloodvessel to place the catheter in the bloodstream. The insertion mechanism34 also includes a blunt cannula 62 coupled to a cannula control tube64, both of which are shown in a retracted position in FIG. 3. The bluntcannula 62 surrounds the sharp needle 50 and its use will be explainedin further detail below. Near the proximal end 66 of the insertionmechanism, locking slots 68 can be seen that will permanently lock tabs70 of the cannula control tube 64 into the wall of the needle tube 48when the cannula control tube 64, and the blunt cannula 62, have beenfully extended, as will be shown in more detail in FIG. 9. Also shown inFIG. 3 is a flashback chamber 72 located at the proximal end of thesharp, hollow needle 50. The flashback chamber 72, needle tube 48,cannula control tube 64, and control handle 58 are formed of a clearmaterial so that the contents of the flashback chamber 72 can be seen byan operator of the safety catheter insertion device 30.

As shown in FIG. 3, the sharp needle 50 is in a retracted positionwithin the needle tube 48, and the control handle 58 is also in aretracted position at the proximal end 66 of the needle tube. The tabs70 of the control tube 64 are located proximal to the locking slots 68and therefore, the control tube 64 has not yet been used to extend thesharp needle 50 from the needle tube 48. This is a typical configurationfor an insertion mechanism 34 that is connected to the connector 38 buthas not yet been used to extend the sharp needle 50 through theconnector to perform a venipuncture procedure on a patient.

The connector 38 is now shown in greater detail in FIGS. 4 and 5. Theconnector 38 comprises a housing 73 terminating in an exit port 44 atits distal end, to which the catheter may be attached as shown in FIG.3. At the proximal end of the housing is located a female Luer adapter74 for engagement with a male Luer tip or, in this case, the sharpneedle insertion mechanism 34, as shown in FIG. 3. The adapter 74includes a female Luer port 76 and related externally mounted threads54. The female Luer connection port 76 is configured to receive all ISOstandard male luer fittings, as well as other blunt cannulas or fluidconduit devices.

Located within the housing 73 of the connector 38 is a piston element80. The piston element is resiliently deformable and is captured withinthe housing 73 between the female Luer adapter 74 and a the base 82 ofthe housing 73. The piston element's structure, exemplified in detail inFIGS. 5, 6, and 7, generally includes a piston head section 84 and acompressible, or spring, section 86 (see FIG. 6). The piston headsection 84 includes a piston head 88 that is elliptical in cross-sectionand includes a thick taper-lock portion 90 that is circular incross-section. A marquise-shaped bore 92 is formed in the piston head 88and terminates in an orifice 73 at its proximal end 75.

As is apparent from FIGS. 6 and 7, the marquise-shaped bore 92 isoriented such that its major axis 94 is perpendicular to the major axis96 of the elliptically-shaped piston head 88. This geometry assists innaturally biasing the marquise-shaped bore 92 into its naturally openposition. The naturally open marquise shape of the bore 92 creates anoutward force parallel to the major axis 96 of the elliptical shapedpiston head 88 and an inward force parallel to the minor axis 94. Theinward force tends to compress the piston head 88 in a directionperpendicular to its major axis and thus tends to pull themarquise-shaped bore open when a male luer or other blunt cannulaapplies force to the top 98 of the piston 80 moving the piston into thecenter section of the housing 73, as will be shown later. This isaccomplished by the elliptical-conical shape of the elliptical conicalsection 100 that transforms the axial force applied by the male Luerinto transverse biasing forces. These biasing forces are what assist theopening of the normally open marquise-shaped bore 92.

The dimensions of the elliptical piston head 88 and the marquise-shapedbore 92 are selected such that when the head is constrained into thecircular interior of the ISO Luer taper section 102 of the female lueradapter 74 (see FIG. 5), the bore 92 is completely collapsed and tightlyclosed off from flow. The tapered shoulder 104 of the taper lock section90 contacts the ramp/lock section 106 of the female Luer adapter 74 andprevents the top of the piston head 88 from extending beyond theconnection port proximal surface 108 to make it substantially flush. Theinternal diameter of the center section 110 of the Luer adapter 74 isselected such that, when the piston head 88 is positioned therein (shownin FIG. 9), the piston head is free to resume its elliptical shape. Thisin turn allows the bore 92 to resume its naturally open marquise-shapethereby opening a fluid path through the piston element 80 and theconnector 38.

Prior to use the insertion mechanism 34 is initially in its unaccessedstate or closed position as shown in FIGS. 2 and 3. The compressiblesection 66 is pre-loaded and causes the piston head 64 to be biased intothe ISO Luer taper section 54 of the female Luer adapter 74 of theconnector. The shoulder 104 of the taper-lock section 90 contacts thetapered ramp/lock section 106 of the adapter 74 and prevents the top ofthe piston head 88 from extending beyond the connection port proximalsurface 108 to form a smooth and flush surface. The bore 92 throughoutthe piston head 88 is tightly squeezed shut by virtue of the normallyelliptically shaped piston head being constrained into the circularcross-section of the ISO Luer taper section 54. The sharp pointed endsof the marquise-shaped bore facilitate a tight seal upon compression ofthe bore along its minor axis 96 by compression of the piston head 68along its major axis 94. Further details of the operation of theconnector may be found in U.S. Pat. No. 5,676,346 toLeinsing, referencedabove.

Before connecting the insertion mechanism 34 to the safety catheterdevice 32, the top or proximal surface 108 of the safety catheter device32, including the top surface of the piston, may be cleaned. Forexample, a sterilizing swipe may be passed over the smooth surfaces. Theinsertion mechanism may then be connected to the safety catheter deviceas shown in FIGS. 2 and 3. However, in another embodiment, the insertionmechanism may already be connected to the safety catheter device at thefactory and no further wiping of the connector will be necessary beforeits use.

The insertion mechanism is connected to the safety catheter device viathreaded connection in the embodiment shown and described herein. Inparticular, as is shown in FIGS. 8 and 9 in greater detail, the distalend 112 of the insertion mechanism 34 includes internal threads 114 thatengage the external threads 54 of the connector. The assembly would thenappear as shown in FIG. 2. However, other connection approaches may befound to be usable.

In FIG. 3, the insertion mechanism 34 is shown in the initial positionwith the control handle 58 located near the proximal end 66 of theinsertion mechanism. The control handle is then grasped by theclinician, such as with a thumb and forefinger, and is slid carefully inthe distal direction. As the control handle progresses in the distaldirection, the flashback chamber 72 contacts the blunt cannula controltube 64, having a first cross-sectional width that is less than across-sectional width of the flashback chamber 72, as shown in FIG. 3,causing the blunt cannula control tube 64 to also move in the distaldirection until its locking tabs 70 engage the locking slots 68 in thewall of the needle tube 48, as shown in FIG. 11. The position of thecontrol handle at this occurrence is shown in FIG. 10. The blunt cannulacontrol tube, then having a second cross-sectional width that is greaterthan the cross-sectional width of the flashback chamber 72, no longerinterferes with the flashback chamber and the flashback chamber 72/sharpneedle 50 can be extended farther. Referring again to FIG. 9, theprotecting action of the blunt cannula 62 can be clearly seen. As thecontrol handle is moved distally as shown in FIGS. 10 and 11, the bluntcannula extends from the needle tube 48 into the female port 56 of thefemale Luer adapter 46 of the connector 38. By pressing the piston head88 of the piston element 80 into the larger diameter center section 110of the connector, the naturally open, marquise-shaped bore 92 of thepiston is permitted to resume its naturally open shape. At the sametime, the blunt cannula 62 is small enough to fit within the bore 92thereby providing protection to the piston head from possible tearing orpuncture that might be inflicted by the sharp needle 50 if it were nothoused within the blunt cannula. It will be noted that the sharp needle50 moves with the blunt cannula 62 into the piston head, as can be seenin FIG. 9. It is at the point of extension into the piston element 80shown in FIG. 9 that the locking tabs 70 of the blunt cannula controltube 64 protrude into the locking slots 68 of the wall of the needletube 59 preventing further extension of the blunt cannula into theconnector 38.

It may also be noted that the blunt cannula has a tapered base section115 that tapers outwardly in the proximal direction. The blunt cannulabase engages an inwardly tapered section 117 at the distal end 112 ofthe insertion mechanism 34; i.e., the section tapers inwardly in thedistal direction. The two tapers are such that the blunt cannula cannotbe removed from the insertion mechanism in the distal direction and theblunt cannula therefore can only extend a predetermined length from thedistal end 112 of the insertion mechanism. Thus the blunt cannulacontrol tube 64 need not be rigidly mounted to the blunt cannula 62.When the blunt cannula control tube 64 is locked in position with thelocking device of the tabs 70 and the slots 68, the blunt cannula isprevented from moving in the proximal direction by the locking device 70and from moving in the distal direction by the tapers 115 and 117.

The above is accomplished with a single distal motion. However, once thelocking tabs 70 have become located within the slots 68, the sharpneedle 50 will be free to extend distally beyond the blunt cannula 62.Then, continuing without interrupting the same distal motion, thecontrol handle 58 is further slid toward the distal end of the insertionmechanism until it reaches the end of its travel, as exemplified inFIGS. 12 and 13. The length of the catheter 36 is selected such that, atthis stage of operation, the distal tip of the sharp needle 50 willprotrude from the catheter 36 a distance sufficient to permit thesuccessful completion of a venipuncture procedure as shown in FIG. 14.Once the catheter has been positioned properly in the patient's vein, asis indicated by the flow of the patient's blood into the attachedflashback chamber 72 for example, the sharp needle 50 is then retractedinto the protective needle tube 48 by moving the control handle 58 inthe proximal direction and locking the control handle in the retractedposition, as is also shown in FIG. 14.

An exemplary locking mechanism is shown in FIGS. 15 and 16. Inparticular, FIG. 15 shows the connection between the control handle 58and the flashback chamber 72. A connection arm 116 provides a rigidconnection between the control handle 58 and the flashback chamber 72,which in turn is connected to the sharp needle 50. Therefore, movementof the control handle will cause movement of the sharp needle.Conversely, securing the control handle in a fixed position will preventmovement of the sharp needle. A control handle locking device isprovided to retain the sharp needle 50 within the needle tube 48 once ithas been retracted. As is seen in FIG. 1, a pair of locking arms 118face each other, yet are spaced apart. A locking notch 120 provides formovement in the proximal direction from the locking arms. Referring nowto FIG. 16, a partial cross-section composite of the locking approach inthis embodiment is shown. Particularly apparent is that the locking arm116 includes a triangularly-shaped anchor segment 122. As the controlhandle is moved in the proximal direction, the point of the anchorsegment moves between the locking arms 118 separating them, and thenmoves into the locking notch. As the bottom of the triangular anchorclears the locking arms 118, they spring back to their closedconfiguration, as seen in FIG. 1, preventing distal movement of thecontrol handle and sharp needle. The sharp needle is then permanentlylocked within the needle tube 48 thereby protecting clinicians or otherswho may handle the insertion mechanism in the future. The insertionmechanism 34 can then be separated from the safety catheter device 32 asshown in FIG. 17, and discarded.

When the control handle 58 has been retracted to the position shown inFIG. 17, the blunt cannula 62 will remain extended. As the needle tube48 is unthreaded from the connector, movement of the blunt cannula inthe proximal direction will permit the spring 86 of the connector toforce the piston head 88 once again into the smaller size female Luerport 76 causing the marquise-shaped bore 92 to close, preventing bloodfrom flowing from the catheter out of the connector 38. A site is nowavailable through the connector 38 to the patient's circulatory system.

Various details have not been discussed above so that clarity of thedescription would be preserved. However, it will be appreciated by thoseskilled in the art that various changes may be made that do not departfrom the scope of the invention. For example, a one way filter or valvemay be included with the flashback chamber 72 so that blood remains inthe chamber when the insertion mechanism is removed from the connector38, as shown in FIG. 17. Referring to FIGS. 18 and 19, the catheter 36is shown permanently attached to the distal port 44 of the connector 38.This reduces the number of components by combining the catheter hub withthe connector housing 38. Another variation if shown in FIGS. 20 and 21in which the piston element 124 includes a normally expanded section 126so that a neutral or positive bolus results when a male Luer tip 128 iswithdrawn from the female port 56. Although a male Luer is shown in FIG.21, the positive bolus connector 130 may accept the blunt cannula shownand described above. Further details of the positive bolus connector ofFIGS. 20 and 21 may be found in application Ser. No. 09/998,383,presently pending, and incorporated herein by reference.

Further, a needle tube 48 was shown and described as providing a sharpneedle protection device located so as to provide a physical barrier atthe sharp tip of the needle to protect users of the insertion mechanismfrom being punctured by the sharp tip. However, other embodiments may bepossible including a self blunting needle in which a dull rod extendsfrom the lumen of the sharp needle past the sharp tip to protect usersfrom the sharp tip.

Although specific embodiments of the invention have been described andillustrated, it will be apparent to those skilled in the art thatmodifications and improvements may be made to the devices disclosedherein without departing from the scope of the invention. Accordingly,it is not intended that the invention be limited, except as by theappended claims.

What is claimed is:
 1. An insertion mechanism for use with a needlelessconnector having a flexible catheter comprising: a needle tube having aproximal end and a distal end, the needle tube configured to removablycouple to the needleless connector; a cannula control tube slidablydisposed within the needle tube between a proximal position and distalposition, relative to the needle tube, the cannula control tubecomprising a passage and a blunt cannula, a portion of the passagecomprising a first cross-sectional width when the cannula control tubeis in the proximal position, and a second cross-sectional width, greaterthat the first cross-sectional width, when the cannula control tube isin the distal position; and a needle movably disposed within the cannulacontrol tube, such that the needle is axially slidable relative to thecannula control tube, the needle comprising a proximal portion having aflashback chamber with a third cross-sectional width that is greaterthan the first cross-sectional width, and a distal tip, wherein theflashback chamber is configured to (i) urge the cannula control tubetoward the distal position as the needle is moved toward the distal endof the needle tube, and (ii) move through the passage when the cannulacontrol tube is in the distal position, such that the distal tip extendsbeyond the distal end of the needle tube.
 2. The insertion mechanism ofclaim 1, wherein: the needle further comprises a proximal position andan anchor segment; the needle tube further comprises a locking armconfigured to engage the anchor segment when the needle is in theproximal position; and the needle tube and the needle are configuredsuch that the distal tip of the needle is disposed within the needletube and the needle cannot be moved in the distal direction when thelocking arm is engaged with the anchor segment.
 3. The insertionmechanism of claim 2, wherein: the needle tube further comprises anaccess slot with proximal and distal ends; and the needle furthercomprises a handle that extends through the access slot.
 4. Theinsertion mechanism of claim 1, wherein the flashback chamber is fluidlyconnected to the distal tip.
 5. The insertion mechanism of claim 4,wherein the needle tube and the flashback chamber are formed of a clearmaterial.
 6. An insertion mechanism for use with a needleless connectorhaving a flexible catheter comprising: a needle tube having a proximalend and a distal end, the needle tube configured to removably couple tothe needleless connector; a cannula control tube, having a passage and ablunt cannula, slidably disposed within the needle tube between aproximal position and a distal position, a portion of the passage havinga first cross-sectional width in the proximal position and a secondcross-sectional width in the distal position, the second cross-sectionalwidth being larger than the first cross-sectional width; and a needlemovably disposed within the cannula control tube, such that the needleis axially slidable relative to the cannula control tube, and comprisinga distal tip and a proximal flashback chamber fluidly connected to thedistal tip, wherein the flashback chamber comprises an outer surfacehaving a third cross-sectional width that is between the first andsecond cross-sectional widths of the passage of the cannula controltube.
 7. The insertion mechanism of claim 6, wherein the needle and thecannula control tube are configured such that the distal tip of theneedle does not extend beyond the blunt cannula when the cannula controltube is in the proximal position.
 8. The insertion mechanism of claim 6,wherein the distal tip of the needle extends beyond the distal end ofthe needle tube when the cannula control tube is in the distal position.9. The insertion mechanism of claim 6, wherein: the needle furthercomprises a proximal position and an anchor segment; and the needle tubefurther comprises a locking arm configured to engage the anchor segmentwhen the needle is in the proximal position.
 10. The insertion mechanismof claim 9, wherein the needle tube and the needle are configured suchthat the distal tip of the needle is disposed within the needle tube andthe needle cannot be moved in the distal direction when the locking armis engaged with the anchor segment.
 11. The insertion mechanism of claim9, wherein: the needle tube further comprises an access slot withproximal and distal ends; and the needle further comprises a handle thatextends through the access slot.
 12. The insertion mechanism of claim 6,wherein the needle tube and the flashback chamber are formed of a clearmaterial.